Vaillant VR33 with Arotherm Plus

[J1mbo]

Any ideas if the VR33 could be used to connect third party smart system via Opentherm to the Arotherm Plus series.

 

The goal is to get variable flow temperature to provide faster heating while minimising average system flow temperature, hence maximising efficiency.

[gavztheouch]

Did you install an arotherm plus? I have a quote for a 7kw system. I was surprised by the cost of installation at roughly 6k for maybe two days work. Feels like RHI is creating a lot of fluff in prices. Anyway there is not a lot of info on these new units in forums or YouTube yet. How do you find yours? Is it quite when running? The scop looks good for these units, have you found it efficient? Thanks

[Dan F]

On 17/11/2020 at 13:06, J1mbo said:

Any ideas if the VR33 could be used to connect third party smart system via Opentherm to the Arotherm Plus series.

 

What did you do regarding integration in the end?   Vaillant talk about support for EEBus and Modbus using their newer controllers, but I can't find documentation anywhere.

 

Also, our installer has told me that the controller supports 3rd-party "call for heat" but doesn't support 3rd-party "call for cool". 

 

Plans is to use Loxone for all heating control, and there want Loxone to send "call for heat" and "call for cool" to the ASHP controller (either via API, EEBus, Modbus or digital output).

[J1mbo]

@Dan F - the system is built around ebus. Vaillant do provide the vr920 Internet gateway option but there is no published API.

 

But, I would think carefully before going 3rd party controls. The system is designed o work with the vr700 which provides the flow curves based on outside, inside, and set point. Without this control the system will need to always be set to a higher flow temp to achieve an acceptable warm up period and hence the efficiency will be lower. Also bear in mind a significant volume of water is needed in the system circulating to avoid short cycling.

 

hope that helps.

[J1mbo]

@gavztheouch - yes got the 12kW. Bear in mind there is work and overheads involved for the MCS scheme in the installers side. In my case installation took quite a while so whilst the quote was similar, it ended up being good value in the end and especially since the RHI scheme pays back almost all of it.

 

System is quiet definitely. It doesn’t seem to meet it’s quoted numbers - looks like it will be about 20% more in the end. My concern with a 7kW unit would be hot water recovery time, that’s not a lot of power especially if you’re planning to use the (default) eco mode for DHW which is about 45% output.

[Dan F]

On 08/04/2021 at 08:01, J1mbo said:

@Dan F - the system is built around ebus. Vaillant do provide the vr920 Internet gateway option but there is no published API.

 

But, I would think carefully before going 3rd party controls. The system is designed o work with the vr700 which provides the flow curves based on outside, inside, and set point. Without this control the system will need to always be set to a higher flow temp to achieve an acceptable warm up period and hence the efficiency will be lower. Also bear in mind a significant volume of water is needed in the system circulating to avoid short cycling.

 

hope that helps.

 

I want to avoid interfacing with ASHP directly via ebus, but instead idea is to interface with Vaillant controller via modbus or something called eebus. 

 

Loxone will have all room/slab temperatures, weather data, as well as data on state of charge of Mixergy so should be able to coordinate everything, rather than relying on Vaillant ecosysten or more basic call for heat.

 

So wondered what others are doing.. are you using Vaillant thermostat(s) or third party call for heat to Vaillant controller?

Edited April 10, 2021 by Dan F

[MikeSharp01]

On 08/04/2021 at 08:01, J1mbo said:

the system is built around ebus. Vaillant do provide the vr920 Internet gateway option but there is no published API.

Just poking this thread as it looks like there is now an API and a home assistant integration but no Homely integration. We are being offered a vailliant heatpump for our DHW / UFH and I would like to make sure that I can get control of it. Anybody got any experience of the vaillant API development groups work?

[Dan F]

22 minutes ago, MikeSharp01 said:

Just poking this thread as it looks like there is now an API and a home assistant integration but no Homely integration. We are being offered a vailliant heatpump for our DHW / UFH and I would like to make sure that I can get control of it. Anybody got any experience of the vaillant API development groups work?

 

I haven't use the myVAILLANT home assistant integration. This only works with the updated myVailant gateway and mine was only upgraded last week.

 

If you want full geek-level access to everything though ebusd [1] is the best option given Vaillant don't offer a modbus interface. It's not vaillant supported and can be a little tricky depending to up and running, but it does have Home Assistant and Loxone integration which makes it easy to use once you have configuration sorted.

 

[1] https://github.com/john30/ebusd

Edited March 17 by Dan F

[JohnMo]

25 minutes ago, MikeSharp01 said:

are being offered a vailliant heatpump for our DHW / UFH and I would like to make sure that I can get control of it. Anybody got any experience of the vaillant API development groups work?

Why wouldn't you just use the controller that comes with it. If doing UFH basically run long and slow or if on a longish time of use tariff like E7 and batch charge, having a battery helps keep flow temps low as you can run longer and still keep cheap tariff effective. Anything else is just making it complicated for the sake of it.

[MikeSharp01]

1 hour ago, JohnMo said:

Why wouldn't you just use the controller that comes with it. If doing UFH basically run long and slow or if on a longish time of use tariff like E7 and batch charge, having a battery helps keep flow temps low as you can run longer and still keep cheap tariff effective. Anything else is just making it complicated for the sake of it.

I think I want to somewhat follow in the Homely footsteps and use dynamic trading - such @TerryE and others have been looking at through Octopus to control the ASHP / UFH / DHW use and SOLAR generation in association with APIs like openweathermap for more than direct weather compensation and then some basic AI's at the outset to to optimize it while improving this heuristic functionality through data gathering.  

[Dan F]

13 minutes ago, MikeSharp01 said:

I think I want to somewhat follow in the Homely footsteps and use dynamic trading - such @TerryE and others have been looking at through Octopus to control the ASHP / UFH / DHW use and SOLAR generation in association with APIs like openweathermap for more than direct weather compensation and then some basic AI's at the outset to to optimize it while improving this heuristic functionality through data gathering.  

 

If you want to do things like directly control flow temperature and/or limit compressor speed etc. programmatically then ebus integration is going to allow you to do more.  Also, when it comes to cooling the standard controls (and associated API that you'd have access to via myVaillant integration) are pretty limited and don't use weather compensation making cooling control with a passive slab very hard.

 

Over the summer I implemented my own external control (via ebus + loxone) that used slab temp and day ahead forcast to control cooling. I used on/off control with hysteris to target a caclculated target slab temperature rather than weather compensation.  This yeah though, I'll have a go at implementing weather compensation for cooling.

 

 

[MikeSharp01]

27 minutes ago, Dan F said:

via ebus + loxone)

Does that mean you need loxone to access ebus or are the ebus electrical and protocol standards published somewhere. 

[JohnMo]

50 minutes ago, MikeSharp01 said:

APIs like openweathermap for more than direct weather compensation and then some basic AI's at the outset to to optimize

 

29 minutes ago, Dan F said:

Over the summer I implemented my own external control (via ebus + loxone)

Think you are all trying too hard, tried various ways of doing WC, so far the most accurate (house temp stability) and cheapest to run is a set flow temp and a good 0.1 hysteresis thermostat. Cooling just flow at 15  to 16 degs, which is above dew point generally and you get a CoP of about 6 or 7.

[Dan F]

24 minutes ago, JohnMo said:

Think you are all trying too hard, tried various ways of doing WC, so far the most accurate (house temp stability) and cheapest to run is a set flow temp and a good 0.1 hysteresis thermostat. Cooling just flow at 15  to 16 degs, which is above dew point generally and you get a CoP of about 6 or 7.

 

I tried this, but with with UFH in 200mm concrete reaction time was too slow for room thermostat.  Next approach I wanted to try was external control (with hysteresis) using slab temperature instead of room temperature, but Vaillant (at the time anyway) didn't support any sort of external control for cooling leaving me with no option but to control cooling via ebus using slab temperature (with target temp based on outdoor temp)

 

The day ahead calculation was added afterwards as an optimization to ensure the slab wasn't cooled too much if the following day wasn't going to be as hot.  This was really only required because of the huge mass of the slab.

Edited March 17 by Dan F